A phase adjustment circuit for discretely adjusting a phase of a data signal and that of a clock signal, the phase adjustment circuit including: a delay line for delaying the clock signal to produce a delayed clock signal; a phase comparator for comparing the phase of the data signal with that of the delayed clock signal; a delay control section for outputting a delay control signal based on the comparison result from the phase comparator; and a delay control section for outputting a delay control signal based on a frequency of the clock signal. The delay line determines a delay amount of the delayed clock signal with respect to the clock signal based on the control signals.